It is an instance of javax.servlet.jsp.PageContext. Using this object you can find attribute, get attribute, set attribute and remove attribute at any of the below levels –
- JSP Page – Scope: PAGE_CONTEXT
- HTTP Request – Scope: REQUEST_CONTEXT
- HTTP Session – Scope: SESSION_CONTEXT
- Application Level – Scope: APPLICATION_CONTEXT
Quick links:
Methods of pageContext Implicit Object
- Object findAttribute (String AttributeName): This method searches for the specified attribute in all four levels in the following order – Page, Request, Session and Application. It returns NULL when no attribute found at any of the level.
- Object getAttribute (String AttributeName, int Scope): It looks for an attribute in the specified scope. This method is similar to findAttribute method; the only difference is that findAttribute looks in all the four levels in a sequential order while getAttribute looks in a specified scope. For e.g. – In the below statement the getAttribute method would search for the attribute “BeginnersBook” in Session scope (or Session level/layer). If it finds the attribute it would assign it to Object obj else it would return Null.
Object obj = pageContext.getAttribute("BeginnersBook", PageContext.SESSION_CONTEXT);Similarly the method can be used for other scopes too –
Object obj = pageContext.getAttribute("BeginnersBook", PageContext. REQUEST_CONTEXT); Object obj = pageContext.getAttribute("BeginnersBook", PageContext. PAGE_CONTEXT); Object obj = pageContext.getAttribute("BeginnersBook", PageContext. APPLICATION_CONTEXT); - void removeAttribute(String AttributeName, int Scope): This method is used to remove an attribute from a given scope. For example – The below JSP statement would remove an Attribute “MyAttr” from page scope.
pageContext.removeAttribute(“MyAttr”, PageContext. PAGE_CONTEXT);
- void setAttribute(String AttributeName, Object AttributeValue, int Scope): It writes an attribute in a given scope. Example – Below statement would store an Attribute “mydata” in application scope with the value “This is my data”.
pageContext.setAttribute(“mydata”, “This is my data”, PageContext. APPLICATION_CONTEXT);
Similarly this would create an attribute named attr1 in Request scope with value “Attr1 value”.
pageContext.setAttribute(“attr1”, “Attr1 value”, PageContext. REQUEST_CONTEXT);
pageContext Implicit Object Example
index.html
Here we are simply asking user to enter login details.
<html> <head> <title> User Login Page – Enter details</title> </head> <body> <form action="validation.jsp"> Enter User-Id: <input type="text" name="uid"><br> Enter Password: <input type="text" name="upass"><br> <input type="submit" value="Login"> </form> </body> </html>
validation.jsp
In this page we are storing user’s credentials using pageContext implicit object with the session scope, which means we will be able to access the details till the user’s session is active. We can also store the attribute using other scope parameters such as page, application and request.
<html>
<head> <title> Validation JSP Page</title>
</head>
<body>
<%
String id=request.getParameter("uid");
String pass=request.getParameter("upass");
out.println("hello "+id);
pageContext.setAttribute("UName", id, PageContext.SESSION_SCOPE);
pageContext.setAttribute("UPassword", pass, PageContext.SESSION_SCOPE);
%>
<a href="display.jsp">Click here to see what you have entered </a>
</body>
</html>
display.jsp
In this JSP page we are fetching the stored attributes using getAttribute method. The point to note here is that we have stored the attributes with session scope so we must need to specify scope as session in order to fetch those attribute’s value.
<html>
<head>
<title>Displaying User Details</title>
</head>
<body>
<%
String username= (String) pageContext.getAttribute("UName", PageContext.SESSION_SCOPE);
String userpassword= (String) pageContext.getAttribute("UPassword", PageContext.SESSION_SCOPE);
out.println("Hi "+username);
out.println("Your Password is: "+userpassword);
%>
</body>
</html>
Screenshots of the example’s output:
Login page where we are receiving User-Id and Password from user.
A page with details page link –
User Credentials display page which we have passed from login page to this page through pageContext instance.
If you have any questions regarding pageContext implicit object, feel free to ask by dropping a comment below. We will be more than happy to assist you!!
Sir thanks a lot for your example of pageContext, I tried many times but I had confusion about that, but after reading your example it is now clear to me.
Thanks
Thanks Varun :)
I am happy that it helped you.
good explanation..
thank you so much sir ………it’s a good explanation …..
What is the difference between pageContext and page…and I heard that that PageContext.SESSION_CONTEXT not SESSION_SCOPE
Good Explanation sir, now my doubts got cleared thank u so much
We already have request and session implicit object. But again why we are using pagecontext implicit object